"Turn out the lights" is a common phrase used to describe the act of switching off a light source. However, there are a variety of synonyms one can use to convey the same message. For example, "switch off," "shut off," "power down," "cut the power," "douse the lights," "extinguish the lights," "put out the lights," "darken the room," and "dim the lights" are all alternative phrases one can use to instruct someone to turn off a light. These synonyms can be particularly useful when writing poetry or prose and want to avoid using the same phrase repeatedly.